WO2021254902A1

WO2021254902A1 - Method and plant for concrete preparation

Info

Publication number: WO2021254902A1
Application number: PCT/EP2021/065781
Authority: WO
Inventors: Hans-Jörg Fischer
Original assignee: Fischer Hans Joerg
Priority date: 2020-06-16
Filing date: 2021-06-11
Publication date: 2021-12-23
Also published as: DE102020115873A1

Abstract

The invention relates to a method and a plant (6) for the preparation of concrete from a building (31), wherein – concrete is sorted out of a total demolition material (42) of a demolished building (31), - the sorted-out concrete is broken up in a crushing plant (5) such that a concrete crush is produced, - the concrete crush is separated into fractions with different particle size ranges and – depending on the particle size of the concrete crush, at least some of this crush is reused to produce concrete. According to the invention, the concrete sorted out of the total demolition material (42) is crushed in a preparation plant (6) into material having a particle size of between 0 and <40 mm, preferably between 0 and <35 mm, more preferably between 0 and 32 mm and separated into a stone portion (60), a concrete-sand portion (61) and a dust portion (62), the dust portion (62) having a particle size of <0.063 mm, the concrete-sand portion (61) having a particle size of 0.063 mm to 4 mm and the stone portion (60) having a particle size of > 4 mm and all portions (60, 61, 62) being reused to produce fresh concrete.

Description

Process and plant for concrete preparation

The present invention relates to a method for processing concrete of a building, with concrete being sorted out from a total demolition material of a demolished building, the sorted concrete being broken up in a crushing plant, so that a concrete break-up results, the concrete break-up into several fractions is separated with different grain size ranges and, depending on the grain size range of the concrete break-up, this is at least partially reused for the production of concrete.

The invention also relates to a plant for processing concrete of a building according to the above-mentioned method, the plant comprising: a crushing plant for breaking up concrete that was previously sorted out of a total of demolition material (42) of a demolished building (31) so that a concrete break-up results, and a separation stage to separate the broken up concrete into several fractions with different grain sizes.

Cement is used as a binding agent in building materials. If you mix it with water, sand and an aggregate (e.g. gravel or chippings), you get concrete. On the other hand, if you leave out the aggregate and add only water and sand, then mortar is created.

The conventional process for the production of concrete in a concrete plant provides that cement, sand and aggregates are mixed with water and a so-called fresh concrete or ready-mixed concrete is produced. The ready-mixed concrete is driven to a construction site and processed there, e.g. to erect structures, e.g. in the form of residential buildings or structures from the areas of infrastructure, industry, transport, etc.

When the life of the structure has ended and it is demolished, the concrete is sorted out of the total demolition material. This usually takes place on site at the demolition site, for example by means of an excavator or other suitable device. Furthermore, a. the sorted out concrete material either on site at the point of origin with a conventional crushing plant to a grain size of e.g. 0-45 mm or 0-63 mm and directly, ie without sieving and separating into fractions of different grain sizes, back on the construction site as a ballast substitute used, or b. the concrete material is driven to concrete recycling sites, where it is also broken with a conventional crushing plant and then divided into fractions of different grain sizes by means of a screening plant. In particular, the concrete material is separated into fractions of a) 0-8 mm, b) 8-22 mm, and c) 22-45 mm. Only the so-called concrete recycling split with a grain size of 8-22 mm can be reused for the production of concrete and replaces ballast material or natural chippings in the production of fresh concrete in concrete plants. The remaining broken up material with a grain size of 22-45 mm is used either in road construction as a ballast substitute or on construction sites as work space backfilling. The Material with a grain size of 0-8 mm is used as backfilling material for pipelines or disposed of in landfills.

The well-known production of concrete and the limited possibilities for reusing concrete demolition in concrete production mean that concrete is not considered environmentally friendly, especially with regard to the carbon dioxide (C0 ₂ ) emissions that occur during cement production . The present invention is therefore based on the object of making concrete production more environmentally friendly and less expensive, in particular to improve the CCV balance of concrete.

To solve this problem, a processing method for concrete with the characteristics of claim 1 is proposed. Based on the processing method of the type mentioned at the beginning, it is proposed in particular that the concrete sorted out of the total demolition material in a processing plant in material with a grain size between 0 and <40 mm, preferably between 0 and <35 mm, particularly preferably between 0 and 32 mm, broken and separated into a rock fraction, a concrete-sand fraction and a dust fraction, the dust fraction having a grain size of <0.063 mm, the concrete-sand fraction a grain size of 0.063 mm to 4 mm and the rock fraction a grain size of > 4 mm and at least one of the parts can be reused for the production of fresh concrete.

The processing plant preferably comprises a further crushing stage, which breaks the concrete material (with a grain size of 0-45 mm or 0-63 mm) to a finer grain size, e.g. to 0 to <40 mm, in particular to 0 up to <35 mm, preferably to 0 to 32 mm. All or part of the material from the crushing plant is fed into the further crushing stage of the processing plant. Of course, it would also be conceivable that the concrete material sorted out of the total demolition material in the crushing plant immediately to the finer grain size, e.g. to 0 to <40 mm, in particular to 0 to <35 mm, preferably to 0 to 32 mm, is broken up. This would only require a modification of the crushing plant; the further crushing stage of the processing plant could be dispensed with.

The concrete material broken up further to the finer grain size is then separated into fractions of different grain size ranges in a separation stage of the processing plant. The entire further broken up concrete material is preferably divided into at least three fractions with different grain size ranges. The further broken up concrete material is particularly preferred in a) a dust fraction, b) a concrete-sand fraction with a grain size of preferably <0 to 4 mm, and c) a rock fraction with a grain size of preferably 4 to <40 mm, in particular 4 to <35 mm, preferably 4 to 32 mm, separated. The dust preferably has a grain size of <0.063 mm. Thus, the concrete sand preferably has a grain size of 0.063 to 4 mm. The fractionated concrete material obtained in this way can be reused in whole or in part for the production of concrete and does not have to be used for road construction or on construction sites or disposed of in landfills. The various fractions roughly correspond to the components that are required for conventional production of fresh concrete of the type described above, except that the recycled components obtained from the concrete material are used instead of new natural aggregates.

The dust content can be reused in different ways:

1. As a filler.

As a filler, the dust content can be mixed into the fresh concrete as an additive. For example, <5% of the dust content can then be added directly to the fresh concrete. This addition can take place, for example, directly in the concrete plant. When used as a filler, the dust content improves the workability, for example suppleness, of the fresh concrete.

2. As an aggregate in the cement works, in the cement production: For cement production, limestone is usually crushed and burned in a furnace, for example a rotary kiln (for example at approx. 1000 ° C.). This creates cement clinker. This cement clinker can be removed from the kiln and then ground. The quality of the cement clinker and ultimately also of the cement is determined by the degree of grinding and the associated grain size distribution. It is now permissible to add an aggregate to the cement clinker. According to the invention, the dust fraction is now added to the ground cement clinker as an aggregate, preferably with a fraction of <5% by weight.

In addition or as an alternative, provision can also be made for the dust content to be added to the limestone. The crushed limestone can then be burned together with the dust fraction. For example, it is possible that the dust fraction is mixed with the crushed limestone and the mixed fraction is fed into the furnace. However, it is also conceivable that the comminuted limestone and the dust fraction are added to the furnace at different times and / or locations. For example, it is conceivable that the dust fraction makes up a mass fraction of <30% by weight of the total fraction of the material introduced into the furnace. Accordingly, it can be provided, for example, that the crushed limestone makes up a mass fraction of> 70% by weight of the total. The limestone and the dust fraction are burned in the kiln, which increases the hydraulic activity of both the dust fraction and the limestone to form an effective cement clinker.

This results in a considerable reduction in _{CO 2.} This is due to the fact that the CO2 bound in the dust component is no longer released during the burning process, in contrast to the C0 ₂ component of the raw material (limestone) from the quarry.

The different fractions (stone share, concrete-sand share, dust share) with the three different grain sizes can preferably be reused 100% for the production of fresh concrete. The rock material with a grain size of about 4 to <40 mm replaces the corresponding natural material (gravel or chippings) from quarries or gravel works. The concrete sand with a grain size of> 0 to 4 mm replaces natural sand from sand pits or crushed sand from crushed stone works. The dust component replaces filler in fresh concrete and / or can be used in cement production (see above).

Filler are a subgroup of rock flour. They are among the almost inactive substances and have a filler effect in the grain structure of the concrete. Filler are mineral substances with a grain size of usually <0.125 mm, preferably <0.0625 mm, which are obtained from rocks such as lime, quartzitic sandstone or porphyry. If rock powder is used to fill asphalt, concrete components or ready-mixed concrete, we speak of fillers in accordance with DIN EN 13043 or DIN EN 12620. Rock powder as cement filler in accordance with DIN EN 12620 is used as a concrete additive. Rock powder has a predominantly physical effect in concrete (e.g. to achieve a filler effect in the grain structure of the concrete) and influence, in particular improve, the processing behavior of the concrete, among other things.

According to an advantageous further development of the invention, it is proposed that during the preparation stage when breaking up the broken concrete into material with a grain size between 0 and <40 mm, during the preparation stage, cement stone is separated from the filler grain of the concrete and the dust component includes the cement stone. The cement stone is advantageously separated from the filler grain of the concrete in a roller mill, in particular a vertical roller mill. After the cement paste has been separated from the filler grain, the cement paste is fine-grained to dust-like (both are referred to as dust in the context of the present patent application) with a large reactive surface.

Cement glue envelops the stone grains, fills the flea spaces and makes the fresh concrete workable. The hardening of the cement paste creates the cement stone in the hardened concrete. The composition of the cement paste has a great influence on the physical properties of the hardened concrete. The filler grain has, for example, a diameter d = 0.315 x D, where D is the diameter of the coarse grain of the concrete. In practice, coarse grain and fine grain deviate from the spherical shape and the coarse grains and fine grains each have different sizes from one another, so that the fine grain is preferably not larger than about 1/7 of the average coarse grain diameter. Aggregates for concrete are standardized in DIN EN 12620.

The cement stone but also the concrete sand contain calcium oxide CaO which has not yet been further oxidized, e.g. in the form of calcium silicate flydrates (CaO S1O2), calcium aluminate flydrates (CaO AI ₂ O ₃ ) and / or calcium / iron oxide flydrates (CaO Fe ₂ 03).

The main component of the raw material mixture for cement production is calcium carbonate or lime (CaCOs). The calcium carbonate content of the mixture for the production of cement should be at least 76-78% by mass.

According to a preferred embodiment of the invention, it is proposed that after the breaking up of concrete into material with a grain size between 0 and <40 mm during the processing stage, the dust fraction is treated with carbon dioxide, with calcium oxide contained in the dust fraction increasing with the carbon dioxide Lime reacts. In a corresponding manner, it is also advantageous if, after the breaking up of concrete into material with a grain size between 0 and <40 mm, the concrete-sand portion is also exposed to carbon dioxide during the preparation stage, in which case the concrete-sand portion The calcium oxide contained in it reacts with the carbon dioxide to form lime.

The calcium oxide (CaO) contained in the separated and severely crushed cement stone is able to absorb carbon dioxide (CO2). The CO2 can be taken from the ambient air or it can also be added in a targeted manner. During this carbonation of the cement paste, the calcium oxide reacts to form lime (CaC0 ₃ ).

CaO + C0 ₂ -> CaC0 ₃ The lime is a natural Ca compound and is then available for the further process of cement production.

During cement production, limestone = lime (CaCC ^) + clay + fuel = cement clinker and carbon dioxide (CO2) is released. With the present invention, the cycle is now closed in that the cement filler and the sand absorb CO2 again and _{lime (CaCOs) is created from a CaO + C0 2} compound, as with the starting product, limestone.

The concrete-to-concrete process described above and the binding of CO2 in a stable natural CaC03 compound serve to avoid waste and improve the C0 ₂ balance of the concrete. The reduction in _{CO 2} emissions is achieved through short transport routes, through a reduction in the amount of new cement required and through the binding of CO2 emitted, especially from the air.

Furthermore, a processing plant for concrete with the features of claim 9 is proposed to solve the above-mentioned object. Based on the processing plant of the type mentioned at the beginning, it is proposed in particular that the processing plant have a further crushing stage for breaking the concrete sorted out of the total demolition material into material with a grain size between 0 and <40 mm, preferably between 0 and <35 mm, particularly preferably between 0 and 32 mm, and the separation stage separates the material from the further crushing stage into a rock fraction, a concrete-sand fraction and a dust fraction, the dust fraction having a grain size of <0.063 mm, the concrete-sand fraction a grain size of 0.063 to 4 mm and the rock content has a grain size of> 4 mm.

The processing plant is formed to carry out the method according to the invention. In particular, it is proposed that the processing plant separates the cement stone from the filler grain of the concrete when the broken-up concrete is broken down into material with a grain size between 0 and <40 mm, and the dust component includes the cement stone. The cement paste is preferably separated from the filler grain in a roller mill, especially in a vertical roller mill, which is part of the processing plant.

Advantageously, after separating the material from the further crushing stage, the processing plant acts on the dust portion or the cement stone and / or the concrete-sand portion with carbon dioxide, whereby in the dust portion or the cement stone and / or in the concrete The calcium oxide contained in the sand reacts with the carbon dioxide to form lime. The processing plant preferably has at least one CCV receiving unit for the application of the dust component and / or the concrete-sand component with carbon dioxide. This is preferably a closed system in which the dust or concrete sand produced in the processing plant can absorb CO2, so that a stable natural Ca compound (CaCOs) is created. The exposure of the dust content and the concrete sand with CO2 in the at least one CCV intake unit is preferably carried out at ambient pressure (approx. 1,013.25 hPa +/- 30 hPa) and at ambient temperature (approx. 15 ° C +/- 15 ° C). Of course, it would also be conceivable, however, to apply the CCV under an increased pressure (e.g.> 1,500 hPa) and / or with the supply of heat

(Reaction temperature eg> 30 ° C) so that the dust or sand can absorb a larger amount of CO2. It is also conceivable to mix the dust component and / or the sand during the CCV absorption in order to be able to provide a reactive surface over a longer period of time, so that the dust component or the concrete sand has a larger amount Can absorb CO2. The dust content and the sand can be acted upon with CO2 _{in separate C0 2} absorption units or in a common C0 _{2 absorption unit.}

Further features and advantages of the present invention are explained in more detail below with reference to the figures. Show it:

1 shows a cycle for concrete production and recycling comprising the method according to the invention for concrete preparation. 2 shows a mind map of a method known from the prior art for preparing concrete; and

Fig. 3 is a mind map of a method according to the invention for processing concrete.

With reference to a part of FIG. 1 and FIG. 2, a known method for limited concrete preparation is explained in more detail below.

A known process for the filling of concrete in a concrete plant 1 provides that cement 10, sand and aggregates 11 are mixed with water 12 and a so-called transport or fresh concrete is produced. The quantities given in FIG. 2 are only exemplary, but can give an indication of the proportions of the various components for the production of fresh concrete. The concrete usually also comprises a small amount of lime (CaCOs) 13. The ready-mixed concrete is transported to a construction site 3. For example, a concrete mixer 2, a pipe system or the like can be used to transport the concrete. At construction site 3, the concrete is processed, e.g. to erect structures 31 above and below ground, including e.g. residential / administrative / office buildings, structures in the area of transport (e.g. bridges, tunnels, track construction, roads, runways , Airports, train stations, rest stops), infrastructure buildings (e.g. sewers, sewage treatment systems, noise barriers, schools, universities, hospitals) or for erecting or manufacturing parts thereof (e.g. revolving restaurant, concrete sleepers, track bed, etc.).

When the service life of the structure 31 has ended (41 in FIG. 2), its demolition 4 takes place First processing stage 51 a. the concrete material on site at the point of occurrence with a conventional crushing plant 5 broken into material with a grain size of 0-45 mm or 0-63 mm and, for example, used again on construction site 3 as a ballast substitute, or b. the concrete material is driven to concrete recycling sites and the material is also broken there with a conventional crushing plant 5 into material with a grain size of 0-45 mm or 0-63 mm and the material with a grain size of 8/22 (8-22mm) either as Ballast substitute used or partially used as concrete chippings as a substitute for natural chippings in concrete works 1 (53 in Fig. 2); the remaining grains are partly used in road construction (52 in Fig. 2) or disposed of in landfills.

The well-known Fierstellung of concrete and the limited possibilities to reuse concrete demolition in the concrete production lead to the fact that concrete is not considered environmentally friendly, especially in terms of carbon dioxide (C0 ₂ ) emissions. Thanks to the present invention, concrete production is more environmentally friendly and cheaper and the CCV balance is improved.

In the context of the present invention, after sorting out the concrete (4 in Fig. 1) from the total demolition material 42 and after breaking up the concrete in the crushing plant 5, the concrete is broken up preferably with a grain size of 0-45 mm or 0- 63 mm in a processing plant 6 in material with a grain size between 0 and <40 mm, preferably between 0 and <35 mm, particularly preferably between 0 and 32 mm, broken down into a rock grain fraction 60, a concrete-sand fraction 61 and a Dust fraction 62 subdivided. The processing plant 6 is designed to carry out the method according to the invention.

The aggregate fraction 60 preferably has a grain size in a range from approximately 4 to 32 mm and the concrete-sand fraction 61 has a grain size in a range from preferably> 0 to approximately 4 mm. The grain size ranges of the aggregate fraction 60 and the concrete-sand fraction 61 preferably do not overlap (up to about 4 mm: concrete-sand fraction 61 and above: aggregate fraction 60).

The dust fraction 62 preferably has a grain size of <0.25 mm, preferably <0.125 mm, particularly preferably <0.063 mm, the concrete-sand fraction 61 has a grain size of 0.063 mm to 4 mm and the rock fraction 60 has a grain size of> 4 mm. The grain size ranges of the various parts 60, 61, 62 overlap not yourself. Some or all of the portions 60, 61, 62 are reused for the production of fresh concrete.

Preferably, the further breaking up of the concrete material sorted out at the breaking point 4 and broken up to a grain size of 0-45 mm or 0-63 mm in the crushing plant 5 takes place to a grain size in the range of 0- <40 mm in a further breaking stage, the Part of the processing plant 6 is. The further crushing stage preferably comprises a roller mill 67, in particular a vertical roller mill. Roll mills are known per se from the prior art, for example WO 2020/042679 A1, but not for use in the field of concrete recycling. With regard to the construction and operation of the roller mill, express reference is made to this publication, which is hereby also made the subject of the present application.

As a result of the two-stage breaking up of the concrete material sorted out at the breaking point 4, the concrete material can be broken up particularly well and in a manner that is gentle on the machine. Alternatively, however, it would also be conceivable that the crushing system 5 is modified in such a way that it breaks up the concrete material sorted out at the breaking point 4 in a single step to a grain size of 0 to <40 mm. In this case, the modified crushing plant 5 would be part of the processing plant 6 according to the invention.

To separate the concrete material, which is preferably further broken down to a grain size of 0 to <40 mm, into the components 60, 61, 62, a separation stage 66 can be provided, which is also part of the processing plant 6. The components 60, 61, 62 roughly correspond to the components that are required for conventional concrete production of the type described above in the concrete plant 1, except that the recycled components 60, 61, 62 obtained from the concrete material are used instead of new natural aggregates.

Preferably, during the further crushing stage when breaking up the concrete break-up or the concrete material which has already been broken up to a grain size of 0-45 mm or 0-63 mm in the crushing plant 5, is into the concrete material with a Grain size from 0 to <40 mm (process step 63 in Fig. 3) cement stone separated from the filler grain of the concrete. The dust portion 62 comprises the ground cement stone, which can be reused, for example, as a filler (cement filler) for the production of fresh concrete in the concrete plant 1 (70 in FIG. 3).

Aggregates for concrete are standardized in DIN EN 12620. Cement glue envelops the rock grains (filler grain or coarse grain), fills the flea spaces and makes the fresh concrete workable. The hardening of the cement paste creates cement stone. The composition of the cement paste has a great influence on the physical properties of the hardened concrete. After the cement paste has been separated from the filler grain of the concrete, the cement paste is fine-grained to dusty with a large reactive surface.

It is also proposed that after the breaking up of concrete has been broken down into material with a grain size between 0 and <40 mm in the processing plant 6, the dust component 62 and / or the concrete-sand component 61 are exposed to carbon dioxide CO2, with in The calcium oxide CaO contained in the dust component 62 or the concrete-sand component 61 reacts with the carbon dioxide CO2 to form lime CaC03.

The cement stone or the dust component 62 and / or the concrete-sand component 61 contain calcium oxide CaO which has not yet been further oxidized in the form of calcium silicate flydrates (CaO S1O2), calcium aluminate flydrates (CaO AI2O3), calcium / iron oxide Flydraten (CaO Fe ₂ Os) and / or other calcium oxide compounds.

The main component of the raw material mixture for cement production is lime (calcium carbonate: CaCOs). The calcium carbonate content of the mixture for cementing should be at least 76-78% by mass.

In order to apply carbon dioxide CO 2 to the dust portion 62, the processing plant 6 can have a CO 2 pick-up unit 64 (cf. FIG. 1). In a corresponding manner, it is also advantageous if, in the processing plant 6, a CO 2 receiving unit 65 for loading the concrete-sand portion 61 with Carbon dioxide CO2 is provided (see. Fig. 1). It would also be conceivable, however, for the processing plant 6 to have a common CCV receiving unit for applying CO2 to both components 61, 62. The CO2 absorption units 64, 65 are each preferably a closed system in which the dust portion 62 and / or concrete sand 61 generated in the processing stage 6 absorb CO2, so that a stable natural Ca compound ( e.g. CaC0 ₃ ) arises.

The exposure of the dust portion 62 and / or the sand 61 with CO2 takes place preferably at ambient pressure (approx. 1,013.25 hPa +/- 30 hPa) and at ambient temperature (approx. 15 ° C +/- 15 ° C). Of course, it would also be conceivable to apply the CCV at a pressure above ambient pressure (e.g.> 1,500 hPa) and with the supply of heat (reaction temperature, e.g.> 30 ° C) so that the dust portion 62 and / or the sand 61 absorb a larger amount Can absorb CO2. It is also conceivable to mix the dust portion 62 and / or the sand 61 during the CCV uptake so that as much as possible of the dust portion 62 or all of the sand 61 can reach the surface and react with the CO2. This allows a larger amount of CO2 to be absorbed. It would also be conceivable to introduce the CO2 directly into the material of the ground cement stone (dust component 62) or the concrete sand 61 via nozzles.

In particular, the calcium oxide CaO contained in the separated and heavily comminuted cement stone (dust component 62) is able to absorb further carbon dioxide CO2, for example from the air. During this carbonation of the dust component 62, the calcium oxide reacts to form lime.

CaO + C0 ₂ -> CaC0 ₃

The lime CaC0 ₃ is a natural Ca compound and is then available for the further process of concrete / cement production. The ground dust portion 62 replaces part of the newly produced cement (70 in Fig. 3) or can be used as Filler can be used in fresh concrete. As a result, less new cement is required in cement production and less CO2 is released (72 in Fig. 3).

During cement production, limestone = lime (CaCC ^) + clay + fuel = cement clinker and carbon dioxide CO2 is released (71 in Fig. 3). The present invention now closes the cycle that the dust portion 62 and the sand 61 absorb CO2 again and form a CaO + C0 ₂ compound CaC03, as with the starting product, the limestone.

The concrete-to-concrete method described above are used to avoid waste and to reduce the C0 ₂ emission shown in FIG. 1 as well as the binding of CO2 in a stable natural CaC03 connection. The reduction in _{CO 2} emissions is achieved through short transport routes, by reducing the amount of new cement required and by binding the CO2 emitted.

The material fractions (rock 60, concrete-sand 61, (dust fraction 62) 62) with the three different grain sizes that have been crushed to a grain size of 0 to <40 mm from the concrete demolition and then separated can advantageously be 100% reintegrated Concrete plant / cement plant 1 and used there for the production of new concrete. The dust component replaces cement and other additives that are added during the production of concrete. The concrete-sand component 61 with a grain size of> 0 to 4 mm replaces natural sand from sand pits or crushed sand from gravel works. The rock fraction 60 with a grain size of> 4 mm replaces the corresponding natural material from quarries or gravel works. This guarantees 100% recycling of the entire concrete break-up.

Claims

Expectations

1. A method for the preparation of concrete of a building (31), whereby concrete is sorted out from a total demolition material (42) of a demolished building (31), the sorted out concrete is broken up in a crushing plant (5) so that a concrete break-up occurs results, the broken concrete is separated into several fractions with different grain size ranges and, depending on the grain size range of the broken concrete, this is at least partially reused for concrete production, characterized in that the concrete sorted out from the total demolition material (42) in material with a grain size between 0 and <40 mm, preferably between 0 and <35 mm, particularly preferably between 0 and 32 mm, broken and separated into a rock fraction (60), a concrete-sand fraction (61) and a dust fraction (62) where the dust fraction (62) has a grain size of <0.063 mm, the concrete-sand fraction (61) a grain size of 0.063 mm to 4 mm and the rock fraction (60) a grain size of> 4 mm and at least one of the portions (60, 61, 62) can be reused for the production of fresh concrete.

2. The method according to claim 1, characterized in that the rock fraction (60) is used as a substitute for gravel material or natural chippings in the production of fresh concrete.

3. The method according to claim 1 or 2, characterized in that the concrete-sand portion (61) is used as a substitute for natural sand or crushed sand from crushed stone works in the production of fresh concrete.

4. The method according to any one of the preceding claims, characterized in that the dust fraction (62) is used at least partially as a filler (cement filler) and / or at least partially as a cement substitute in the production of fresh concrete.

5. The method according to any one of the preceding claims, characterized in that when breaking up the concrete break-up into material with a grain size between 0 and <40 mm cement stone is separated from the filler grain of the concrete and the dust fraction (62) comprises the cement stone.

6. The method according to claim 5, characterized in that the cement stone is separated from the filler grain of the concrete in a roller mill (67), in particular a vertical roller mill.

7. The method according to any one of the preceding claims, characterized in that after the breaking up of concrete into material with a grain size between 0 and <40 mm, the dust fraction (62) is acted upon with carbon dioxide, wherein in the dust fraction ( 62) contained calcium oxide with the

Carbon dioxide reacts to form lime.

8. The method according to any one of the preceding claims, characterized in that after the breaking up of concrete into material with a grain size between 0 and <40 mm, the concrete-sand fraction (61) is acted upon with carbon dioxide, wherein in the concrete The calcium oxide contained in the sand (61) reacts with the carbon dioxide to form lime.

9. Plant (6) for processing concrete of a building (31), the plant (6) comprising: a crushing plant (5) for breaking up concrete that was previously made from a total demolition material (42) of a demolished building (31) was sorted out, so that a concrete break-up results, and a separation stage for separating the broken up concrete into several fractions with different grain sizes, characterized in that the processing plant (6) has a further crushing stage (67) for breaking the concrete sorted out of the total demolition material (42) into material with a grain size between 0 and < 40 mm, preferably between 0 and <35 mm, particularly preferably between 0 and 32 mm, and the processing plant has a separation stage (66) which converts the material from the further crushing stage (67) into a rock fraction (60), a concrete -Sand- portion (61) and a dust portion (62) separated, the dust portion (62) having a grain size of <0.063 mm, the concrete-sand portion (61) a grain size of 0.063 to 4 mm and the Rock fraction (60) has a grain size of> 4 mm.

10. Plant (6) according to claim 9, characterized in that the processing plant (6) has a roller mill (67), in particular a vertical roller mill, for breaking up the broken concrete into material with a grain size between 0 and <40 mm, wherein the roller mill (67) separates cement stone from the filler grain of the concrete and the dust fraction (62) comprises the cement stone.

11. Plant (6) according to claim 9 or 10, characterized in that the processing plant (6) has a CCV receiving unit (64) which, after separating the material from the further crushing stage (67), applies carbon dioxide to the dust fraction (62), wherein calcium oxide contained in the dust fraction (62) reacts with the carbon dioxide to form lime.

12. Plant (6) according to one of claims 9 to 11, characterized in that the processing plant (6) has a CCV receiving unit (65) which, after separating the material from the further crushing stage (67), the concrete-sand fraction ( 61) acted upon with carbon dioxide, calcium oxide contained in the concrete-sand component (61) reacting with the carbon dioxide to form lime.